DE102016112520A1 - Bearing device for an exhaust gas turbocharger and turbocharger - Google Patents

Abstract

The invention relates to a bearing device for an exhaust gas turbocharger, comprising a first radial bearing (13) and a second radial bearing (14), wherein the radial bearings (13, 14) for the radial mounting of a shaft (8) of the exhaust gas turbocharger (2), with an axis of rotation ( 11), and wherein between the first radial bearing (13) and a turbine wheel (7) of the exhaust gas turbocharger (2) facing radially extending first support wall (17) of the exhaust gas turbocharger (2) for the axial support of the first radial bearing (13 ) and between the second radial bearing (14) and a compressor wheel (6) of the exhaust gas turbocharger (2) facing radially extending second support wall (22) of the exhaust gas turbocharger (2) for axially supporting the second radial bearing (14) has a first discharge gap (18 ) or a second outflow gap (23) is formed. According to the invention for axial and simultaneous radial support and / or to support the radial bearing of the first discharge gap (18) and / or the second discharge gap (23) against the axis of rotation (11) at least partially forming an angle (α), which is larger or less than 90 ° is formed inclined or curved.

Description

The invention relates to a bearing device for an exhaust gas turbocharger of the type specified in the preamble of patent claim 1 and to an exhaust gas turbocharger according to claim 11.

The publication DE 10 2008 033 814 A1 discloses a bearing device for an exhaust gas turbocharger whose radial bearing formed for the radial mounting of a shaft of the exhaust gas turbocharger with a spacer, which is arranged between the two radial bearings, are connected. The entire bearing device is formed in one piece, ie the radial bearings and the spacer are made together. The problem of such a bearing device can be seen in addition to a complex production of the bearing device in the high material costs, since the bearing device, for example, is elaborately elaborated from a blank.

From a between the radial bearing and a radial bearing opposite wall is a lubricant outlet, which has a high flow velocity. This results in a high pressure on sealing rings, which are provided for sealing against a lubricant outlet in a compressor of the exhaust gas turbocharger and a turbine of the exhaust gas turbocharger.

The object of the present invention is to provide an improved bearing device for an exhaust gas turbocharger. Another aspect of the invention is to provide a cost-reduced exhaust gas turbocharger.

This object is achieved by a bearing device for an exhaust gas turbocharger having the features of patent claim 1 and by an exhaust gas turbocharger having the features of patent claim 11. Advantageous embodiments with expedient and non-trivial developments of the invention are specified in the respective subclaims.

The first aspect of the invention relates to a bearing device for an exhaust gas turbocharger with a first radial bearing and a second radial bearing, wherein the first radial bearing and the second radial bearing for radially supporting a shaft of the exhaust gas turbocharger, comprising a rotation axis, are formed and disposed between the two radial bearings, a spacer is. Between the first radial bearing and a turbine wheel of the exhaust gas turbocharger facing, radially extending first support wall of the exhaust gas turbocharger, which serves for axial support of the first radial bearing, and the second radial bearing and a compressor of the exhaust gas turbocharger facing formed radially extending second support wall of the exhaust gas turbocharger, which is designed for the axial support of the second radial bearing, a first outflow gap or a second outflow gap is configured. According to the invention for axial and simultaneous radial support and / or to support the radial bearing of the first discharge gap and / or the second discharge gap with respect to the axis of rotation at least partially to form an angle which is greater or less than 90 °, inclined or curved.

Radial bearings according to the prior art are cylindrical. In other words, that between the radial bearing and the Abstützwandung executed discharge gap is orthogonal to the axis of rotation. As a result, lubricant exiting via the outflow gap emerges from the discharge gap quasi perpendicular to the axis of rotation. As a result of this leakage results in a high pressure on sealing rings, which are associated with the bearing device and should prevent the passage of lubricant into a compressor of the exhaust gas turbocharger and a turbine of the exhaust gas turbocharger.

The advantage of the present invention is the achievement of a targeted outflow of lubricant exiting the discharge gap in a lubricant reservoir of the exhaust gas turbocharger, wherein the targeted outflow is oriented away from the sealing rings. As a result, they are no longer exposed to the high load due to the high back pressure of the lubricant impinging on them. The sloped or bent drainage gaps lead to a Venturi effect, whereby lubricant is sucked in, in particular on the radial bearing which faces the exhaust gas guide section. Thus, it is avoided that the lubricant can penetrate into the exhaust gas guide section.

In order to increase an oil pressure of the lubricant formed between the shaft and the radial bearing, the outflow gap in an exit region of the outflow gap is preferably designed to be inclined or curved.

An embodiment of the first radial bearing and / or second radial bearing, for example, in the form of a truncated cone, whose large base surface is in each case facing the opposite radial bearing, leads to inclined wall surfaces of the radial bearings, which cause an increase of effective bearing surfaces of the radial bearings. The increase in effective bearing surfaces results in increased damping of the rotor during operation of the exhaust gas turbocharger. Furthermore, the rigidity of the bearing is also increased by increasing the effective bearing surfaces. Under the effective storage area is a sum of the actual The shaft opposite bearing surface of the radial bearings and a portion of the wall surface to understand with a aligned in the radial direction frictional force component.

Another advantage is the reduction of high-precision storage areas. The bearing surfaces are due to their inclined and / or bent to the rotation axis training simultaneously as a radial and thrust bearing. In turn, costs can be reduced and thus a cost-reduced exhaust gas turbocharger can be realized. Sloping surfaces reduce the sensitivity of the oil gap to length tolerances. The effect of the length tolerance is less due to the skew and / or bent position. This results in a slower consumption of the lubrication gaps, whereby a greater axial play is brought about and the bearing device is configured overall more robust than in the prior art.

In a further embodiment, the first radial bearing with the spacer and / or the second radial bearing with the spacer rotatably connected.

Advantageously, the first radial bearing and / or the second radial bearing is integrally formed with the spacer.

In a further embodiment, the first discharge gap and / or the second discharge gap has a first wall surface or second wall surface formed by the first radial bearing or a second radial bearing, which wall is inclined with respect to the axis of rotation. Thus, already in the manufacture of the radial bearing on the formation of the discharge gap influence can be taken. Even if a support wall forming the discharge gap and lying opposite the wall surface has an extension direction which is orthogonal to the axis of rotation, an orientation of the lubricant outlet can be influenced.

In a further embodiment of the storage device according to the invention, the first support wall of the shaft or second support wall of the shaft opposite the first wall surface and / or the second wall surface is designed to be complementary to the first wall surface or second wall surface. Thus, a defined discharge gap can be realized for defined influencing of the lubricant pressure in the discharge gap.

In a further embodiment of the storage device according to the invention, the shaft has a shaft ring for forming the first support wall.

In a further embodiment of the bearing device according to the invention, the second support wall is formed by an oil slinger of the exhaust gas turbocharger. The advantage lies in the fact that, since the oil slinger is a manufactured independently of the shaft component, the production of a complementary or only partially complementary formation of the support wall without a significant overhead is possible. Furthermore, an additional centrifugal effect is achieved due to the oblique and / or bent outflow gap.

Another preferred embodiment is the formation of the spacer made of a plastic, resulting in a weight reduction of the bearing device.

The second aspect of the invention relates to an exhaust gas turbocharger with a rotor, wherein the rotor comprises a compressor impeller, a turbine wheel and a shaft rotatably connecting the compressor with the turbine wheel, wherein the rotor is rotatably mounted in a bearing portion with a bearing device. According to the invention, the bearing device is designed according to one of claims 1 to 10.

The advantage of this invention is an increase in damping of the power tool whereby the power tool has improved runnability by being able to run quieter. Furthermore, with the bearing device according to the invention, a rigidity of the rotor tool is increased, as a result of which a resonance frequency of the rotor increases.

Furthermore, a friction loss of the exhaust gas turbocharger with the aid of the improved bearing device is substantially reduced due to the increased damping. This improved or reduced friction power of the exhaust gas turbocharger according to the invention leads, for example, to a reduction in fuel consumption of an internal combustion engine connected to the exhaust gas turbocharger since the exhaust gas turbocharger according to the invention requires a lower exhaust gas mass flow rate in order to achieve a performance of an exhaust gas turbocharger according to the prior art.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawing. The features and combinations of features mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or shown alone in the figures are not only in the respectively indicated combination but also in other combinations or usable in isolation, without departing from the scope of the invention. Identical or functionally identical elements are assigned identical reference numerals. Show it:

1 in a longitudinal section of an exhaust gas turbocharger according to the prior art,

2 in a longitudinal section of a storage device according to the invention in a first embodiment,

3 in a longitudinal section, the bearing device according to the invention in a second embodiment, and

4 in a perspective view of a first radial bearing, a second radial bearing and an integrally formed with the first radial bearing and the second radial bearing spacers of the storage device according to the invention.

A jig 1 an exhaust gas turbocharger 2 According to the prior art is in a first embodiment according to 1 educated. The turbocharger 2 has a flow-through exhaust gas guide section 3 on, which in the operation of the exhaust gas turbocharger 2 from a fluid, usually flows through exhaust gas. The exhaust gas is generally, but not necessarily, a combustion product of an internal combustion engine, not shown.

The exhaust gas turbocharger 2 is a flow-through ble air duct section 4 and a between the exhaust gas guide portion 3 and the air guide section 4 positioned bearing section 5 assigned, wherein in the storage section 5 the power tool 1 is received rotatably.

The running tool 1 includes a compressor wheel 6 and a turbine wheel 7 , which help each other with the help of a wave 8th are rotatably connected. The compressor wheel 6 is in a compressor wheel chamber 9 of the air guide section 4 arranged to suck in generally fresh air. The turbine wheel 7 is in a wheel chamber 10 the exhaust gas guide section 3 rotatably received.

The turbine wheel 7 is during operation of the exhaust gas turbocharger 2 from the exhaust gas guide section 3 flowing through exhaust gas and driven, wherein there is a rotational movement about an axis of rotation 11 of the power tool 1 performs. This rotation is with the help of the shaft 8th on the compressor wheel 6 transferable, which thus simultaneously to the rotational movement of the turbine wheel 7 performs a rotational movement. With the help of the compressor wheel 6 and its rotational movement is drawn in fresh air, which in the air guide section 4 is compressed.

The wave 8th of the power tool 1 is in the warehouse section 5 with the help of a storage device 12 comprising a first radial bearing 13 and a second radial bearing 14 rotatably mounted. In the area of the compressor wheel 6 is furthermore for axial storage not shown in detail thrust bearing in the bearing section 5 added. In the present embodiment, the first radial bearing 13 and the second radial bearing 14 the form of a semifloating warehouse.

The first radial bearing 13 and the second radial bearing 14 are coaxial with the axis of rotation 11 of the power tool 1 arranged, being between the first radial bearing 13 and the second radial bearing 14 a spacer 15 is designed. The spacer 15 , also referred to as a spacer, supports an axial fixation of the two radial bearings 13 . 14 and is one-piece and non-rotating with the two radial bearings 13 . 14 connected.

2 shows a storage device according to the invention 12 in a longitudinal section. The first radial bearing 13 has a first wall surface 16 on which the turbine wheel 7 is formed facing. Between the first radial bearing 13 and a first support wall 17 the wave 8th , which for the axial support of the first radial bearing 13 is formed, there is a first discharge gap 18 in front. About this first discharge gap 18 can lubricate which is used to lubricate the bearing of the tool 1 between the wave 8th and the first radial bearing 13 present, in a lubricant tank 19 flow away. The lubricant basin 19 is via a drainage channel 20 connected to a non-illustrated lubricant circuit of the internal combustion engine.

The second radial bearing 14 has a second wall surface 21 on, wherein the second wall surface 21 the compressor wheel 6 is formed facing. Between the second wall surface 21 and a second support wall 22 the wave 8th , which for the axial support of the second radial bearing 14 is formed, there is a second discharge gap 23 above, about the lubricant in the lubricant tank 19 can drain away. Both drainage gaps 18 . 23 are opposite the axis of rotation 11 under formation of an angle α, which is smaller than 90 °, inclined. Due to the inclined formation of the drainage column 18 . 23 that of one related to the axis of rotation 11 deviates orthogonal training, the lubricant is directly in the direction of the drainage channel 20 directed.

Likewise, the drainage column could 18 . 23 also be formed bent. Also could the drainage column 18 . 23 be formed only partially inclined or bent. It is necessary for the invention to carry out the inclination or bending in such a way that that the lubricant deviates from an orthogonal outflow from the storage device as indicated in the prior art 12 , in particular in an outlet region of the drainage column 18 . 23 is diverted. In other words, that means the first drainage gap 18 and / or the second drainage gap 23 especially in the exit area 27 the drainage column 18 . 23 opposite the axis of rotation 11 formed at least partially with the formation of the angle α, which is greater or less than 90 °, inclined or bent. As a result, a lubricant pressure in the bearing is increased, whereby the bearing capacity of the bearing is increased.

In the illustrated embodiment, the first wall surface 16 and the second wall surface 21 complementary to the first support wall 17 or to the second support wall 22 educated.

The first supporting wall 17 is a wall of a shaft 8th completely comprehensive shaft ring 24 which is integral with the shaft 8th is trained. Likewise, he could also be independent of the wave 8th been made and with the shaft 8th be rotatably attached.

The second support wall 22 is from an oil slinger 25 the exhaust gas turbocharger 2 educated.

The storage device according to the invention 12 is in accordance with a second embodiment 3 configured and is designed in the form of a so-called semi-floating bearing. They turn in one piece with the spacer 15 executed radial bearings 13 . 14 Not. For fixing is a fixing element not shown in detail in a holder opening 28 added.

The drainage column 18 . 23 have a deflection, whereby a comparison with the first embodiment higher dynamic pressure is generated. This increases the carrying capacity. From one between the oil slinger 25 and the storage section 5 trained chamber 29 is sucked in by the generated higher Venturi effect lubricant sucked, whereby a transfer of the lubricant into the exhaust gas guide section 3 can be reduced or eliminated. Furthermore, a speed of the lubricant at the exit area decreases 27 , which reduces the static pressure in the entire lubricant reservoir.

The deflection can also be formed bent.

In 4 is a perspective view of the first radial bearing 13 , the second radial bearing 14 and the one with both radial bearings 13 . 14 integrally formed spacers 15 shown. The radial bearings 13 . 14 are frusto-conical, creating a storage area 26 the radial bearing 13 . 14 can be easily increased without additional space required. The increase of the storage area 26 leads to an improved or increased damping of the tool 1 and to a rigidity of the bearing of the power tool 1 ,

The angle α results in an increase of an effective bearing surface, wherein the bearing surface 26 is part of this effective storage area. If the angle α is formed in the form of a shallow angle, ie its value is less than 45 °, this leads to a substantial increase in the effective bearing surface.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102008033814 A1 [0002]

Claims (11)

Bearing device for an exhaust gas turbocharger, comprising a first radial bearing ( 13 ) and a second radial bearing ( 14 ), whereby the radial bearings ( 13 . 14 ) for the radial mounting of a shaft ( 8th ) of the exhaust gas turbocharger ( 2 ) are formed, and wherein between the first radial bearing ( 13 ) and a turbine wheel ( 7 ) of the exhaust gas turbocharger ( 2 ) facing radially extending first support wall ( 17 ) of the exhaust gas turbocharger ( 2 ) for the axial support of the first radial bearing ( 13 ) and between the second radial bearing ( 14 ) and a compressor wheel ( 6 ) of the exhaust gas turbocharger ( 2 ) facing radially extending second support wall ( 22 ) of the exhaust gas turbocharger ( 2 ) for the axial support of the second radial bearing ( 14 ) a first discharge gap ( 18 ) or a second discharge gap ( 23 ) is formed, and wherein the shaft ( 8th ) a rotation axis ( 11 ), characterized in that for the axial and simultaneous radial bearing and / or to support the radial bearing of the first discharge gap ( 18 ) and / or the second discharge gap ( 23 ) with respect to the axis of rotation ( 11 ) is at least partially formed to form an angle (α) which is larger or smaller than 90 °, inclined or bent. Bearing device according to claim 1, characterized in that the first outflow gap ( 18 ) and / or the second discharge gap ( 23 ) in an exit area ( 27 ) of the discharge gap ( 18 ; 23 ) with respect to the axis of rotation ( 11 ) is at least partially formed to form the angle (α), which is greater or less than 90 °, inclined or bent. Bearing device according to claim 1 or 2, characterized in that between the first radial bearing ( 13 ) and the second radial bearing ( 14 ) a spacer ( 15 ) is trained. Bearing device according to claim 3, characterized in that the first radial bearing ( 13 ) with the spacer ( 15 ) and / or the second radial bearing ( 14 ) with the spacer ( 15 ) is rotatably connected. Bearing device according to one of claims 3 or 4, characterized in that the first radial bearing ( 13 ) and / or the second radial bearing ( 14 ) with the spacer ( 15 ) is integrally formed. Bearing device according to one of the preceding claims, characterized in that the first outflow gap ( 18 ) and / or the second discharge gap ( 23 ) one from the first radial bearing ( 13 ) or one of the second radial bearing ( 14 ) formed first wall surface ( 16 ) or second wall surface ( 21 ), which with respect to the axis of rotation ( 11 ) is inclined. Bearing device according to claim 6, characterized in that one of the first wall surface ( 16 ) and / or the second wall surface ( 21 ) opposite first support wall ( 17 ) the wave ( 8th ) or second support wall ( 22 ) the wave ( 8th ) is formed complementary. Bearing device according to claim 7, characterized in that the shaft ( 8th ) for forming the first support wall ( 17 ) a wave ring ( 24 ) having. Bearing device according to claim 7 or 8, characterized in that the second support wall ( 22 ) from an oil slinger ( 25 ) of the exhaust gas turbocharger ( 2 ) is formed. Bearing device according to one of claims 3 to 9, characterized in that the spacer ( 15 ) is formed of a plastic. Exhaust gas turbocharger with a power tool, wherein the power tool ( 1 ) a compressor wheel ( 6 ), a turbine wheel ( 7 ) and one the compressor wheel ( 6 ) with the turbine wheel ( 7 ) rotatably connecting shaft ( 8th ), wherein the power tool ( 1 ) in a storage section ( 5 ) with a storage device ( 12 ) is rotatably mounted, characterized in that the bearing device ( 12 ) is formed according to one of claims 1 to 10.

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